Delay fuze for spinning projectiles



June 20, 1967 E. w. TLAM DELAY FUZE FOR SPINNING PROJECTILES 5 Sheets-Sheet 1 Filed June 16, 1965 INVENTOR.

ELVIN W. TLAM @we 7% Ld ATTORNEY June 20, 1967 TLAM 3,326,132

DELAY FUZE FOR SPINNING PROJECTILES Filed June 16, 1965 I5 Sheets-Sheet 3 l INVENTOR.

E LVI N W. TLAM ATTORNEY FIGB United States Patent 3,326,132 DELAY FUZE I GR SPINNING IRGEECTILIES Elvin W. 'Ilarn, Excelsior, Minn, assignor to Honeyweii Inez, Minneapolis, Minn, a corporation of lflelaware Filed June 16, 1965, Ser. No. 464,394 4 Claims. (Cl. NZ-30) ABSTRACT OF THE DISQLUSURE This invention relates generally to a delayed arming device for a rnunition fuze and more particularly relates to an easily miniaturized delay fuze for a projectile that is subject to setback forces upon launch, rotational forces during flight, and impact forces at the termination of the flight.

The present invention was designed specifically for use in small caliber projectiles that are fired from a gun barrel and that rotate about a predetermined spin axis during flight. The fuze is extremely safe for normal handling since a series of separate events are required ot effect arming of the fuze. The safety factor is further enhanced in that the fuze does not arm until a predetermined time has elapsed after the projectile is fired. If a malfunction should occur at the time the projectile is fired or if the projectile should hit an object near the gun, the fuze will not detonate since it has not yet armed.

Although this fuze is highly safe, it is also highly reliable and simple to manufacture. Reliability is achieved by utilizing a minimum number of easily manufactured parts. Because of its simplicity, the fuze is also easily miniaturized. Successfully operated models of this fuze have been built in a package that measures /2 inch in diameter by inch in length.

It is therefore a primary object of the present invention to provide a highly safe and reliable delay fuze that can be easily miniaturized.

Other objects of the invention will become apparent from the following specification and claims, and from the accompanying drawings, in which:

FIGURE 1 is a sectional view of the preferred embodiment of the fuze shown in the safe condition and taken along the spin axis of the fuze;

FIGURE 2 is a similar sectional view showing the fuze in the armed condition; and

FIGURE 3 is a sectional view of the fuze taken along line 33 of FIGURE 1 showing the centrifugally operated detents.

Referring now to FIGURE 1, there is disclosed a sectional side view of the invention taken along the spin axis of the fuze and projectile. The fuze and projectile would be launched in the direction shown by arrow It). The subject fuze includes a housing or housing member 12 having a cylindrical chamber 14 formed therein. A first end 16 and a second end 17 of housing 12 are covered by suitable end plates 13 and 19, respectively. A tubular threaded portion 21 extends from end plate 18 to permit assembly of the fuze with the projectile.

Mounted within chamber 14 adjacent first end 16 is a generally cylindrical body member 23, also referred to herein as first member 23. The diameter or lateral dimensions of body member 23 correspond closely to the diameter of chamber 14 so that body member 23 is movable axially with respect to chamber 14. The longitudinal axis of chamber 14 and of body member 23 lies along the spin axis 24 of the projectile.

To facilitate the manufacture of body member 23, it is assembled in two sections 23a and 23b that are connected together to form a single unit.

Formed within body member 23 is a cylindrical chamber 26, the longitudinal axis of which is perpendicular to spin axis 24. Mounted within chamber 26 is a cylindrical rotor or carrier member 27. Rotor 27 is thus designed to rotate about an axis that is perpendicular to spin axis 24. A sectional view of rotor 27 taken along line 3--3 of FIGURE 1 is shown in FIGURE 3.

Also mounted within chamber 14 adjacent second end 17 is a cylindrical piston member 28, also referred to herein as second member 28. The diameter of piston member 28 is somewhat smaller than the diameter of chamber 14 so that piston member 28 is freely movable therein. An annular flexible sealing member 29 is mounted around the periphery of piston member 28. Sealing member 29 is firmly attached to the periphery of piston member 28. Sealing member 29 is made from rubber or other flexible material and has a flexible lip extending therefrom that lies against the inner wall of chamber 14. It can be seen from the drawings that as piston member 28 moves t0- ward first end 16, sealing member Zfl will contract to allow air to escape between the piston and the walls of the chamber. Any movement of piston member 28 toward second end 17, however, will be difiicult since sealing member 29 will expand to trap the air between the piston and end plate 19.

Also mounted in piston member 28 is a restrictor device 31 made from a sintered metal or other porous substance. Restrictor 31 is intended to meter the fiow of air from one side of piston member 28 to the other during movement of piston member 28 toward second end 17.

Mounted at the center of piston member 28 is a firing pin 32. Firing pin 32 extends outwardly from the face of piston member 28 toward first end 15 and lies along spin axis 24. In the safe position of the fuze disclosed in FIG- URE 1, firing pin 32 extends through an opening 33 formed in the center of section 23b of body member 23. The tip of firing pin 32 also extends into a cup 34 that is formed in the periphery of rotor 27.

A detouator 36 is mounted in rotor 27 to extend diametrically therethrough. In FIGURE 1, detonator 36 is out of line with firing pin 32. Rotor 27 is held in this unarmed position or conditioned by firing pin 33 extending into cup 34. In FIGURE 2, rotor 27 is shown in the armed condition in which detonator 35 is in line with firing pin 32.

Mounted between body member 23 and piston member 28 is a coiled spring that tends to force or bias the two members apart. In the safe position of the fuze shown in FIGURE 1, coiled spring 37 has been compressed so that firing pin 32 extends into cup 34. The fuze is held in this safe position by an annular yieldable disk member 38 having the shape of a truncated cone mounted between body member 23 and first end plate 1%. Disk member 38 forces body member 23 toward second end 17 to compress spring 37 and hold piston member 28 against end plate 19. In the safe position of the fuze shown in FIGURE 1, the fuze will not detonate if accidentally dropped since detonator 36 is out of line with body firing pin 34 and a booster charge 39 that is mounted on body member 23. When a setback force is experienced, however, body member 23 and piston member 28 tend to move rearwardly toward first end 16. This pressure causes disk member 38 to flatten out or collapse as shown in FIGURE 2. Disk member 38 is designed so that it will not collapse unless a force of predetermined magnitude acts on it for a predetermined time. Ordinary shocks such as those experienced during handling are not sufficiently high or suificiently prolonged to cause collapse of disk member 38.

The preferred embodiment of this fuze was intended for use in a rotating munition. To utilize the centrifugal force developed by the rotating munition for safing purposes, a pair of spring loaded detents 41 and 42 are mounted in body member 23 as shown in FIGURE 3. Detents 41 and 42 extend into openings in opposite faces of rotor 27 to hold rotor 27 in the unarmed position shown in FIGURE 1. After the projectile is fired, the centrifugal forces developed by the rotating projectile cause detents 41 and 42 to spin out and release rotor 27. Detents 41 and 42 are thus an added safety factor tending to hold rotor 27 in the unarmed position until the projectile is in flight.

Means are also provided to rotate rotor 27 from the unarmed to the armed position. Rotor 27 is unbalanced by virtue of four rod shaped members 43a, 43b, 43c and 44 that are mounted on opposite sides of rotor 27. Members 43 and 44 are constructed from a heavier material than that used in the rotor so that the rotor will be unbalanced as it spins about spin axis 24 during flight. Members 43 are fixedly mounted in rotor 27. Member 44, however, is mounted in an open slot 45 in the periphery of rotor 27. In FIGURE 1 it can be seen that as the fuze spins about spin axis 24, the centrifugal force will tend to drive members 43 and 44 outwardly from the spin axis, causing rotor 27 to rotate in a clockwise direction to the position shown in FIGURE 2. In the position shown in FIGURE 2, rod member 44 has been driven into a slot 46 that is formed in the wall of chamber 26. Because of the centrifugal force that is present, rod member 44 will be driven into slot 46, tending to lock rotor 27 in the armed position shown in FIGURE 2.

Operation The fuze is stored and handled while in the safe position shown in FIGURE 1. In the safe position, disk member 38 forces body member 23 toward second end 17 to compress spring 37 and force piston member 28 against end plate 19. In this position, rotor 27 is in the unarmed condition with detonator 36 out of line with firing pin 32. Firing pin 32 extends into cup 34 in rotor 27 to hold rotor 27 in the unarmed position. Rotor 27 is also held in the unarmed position by detends 41 and 42 as shown in FIGURE 3. Even if detonator 36 should accidentally explode, the entire projectile will not be detonated since detector 36 is out of line with booster charge 39.

When the projectile is fired in the direction shown by arrow 10, the setback force causes body member 23 and piston member 28 to move rearwardly in chamber 14 toward first end 16. When the required force is achieved over the required time, disk member 38 will collapse to the position shown in FIGURE 2. Both body member 23 and piston member 28 then move toward first end 16 under the continued influence of the setback force. No delay will be experienced in the movement of these two members toward first end 16 after disk member 38 collapses, since flexible sealing member 29 will allow air to freely pass around piston member 28.

At the same time that the setback force is being experienced, the projectile will begin to rotate. The centrifugal forces developed by the rotating projectile will cause detents 41 and 42 to spin outwardly to release rotor 27 As the setback force begins to dissipate, coiled spring 37 will begin to overcome the force caused by setback acting on piston member 28. Coiled spring 37 will thus drive piston member 28 toward second end 17. At this time, however, air is trapped between piston member 28 and end plate 19 since flexible siding member 29 seals the opening between the piston and the wall of the chamber. The trapped air is thus forced through restrictor means 31 at a controlled rate. As piston member 28 slowly moves toward second end 17, firing pin 32 is gradually drawn out of cup 34 in rotor 27. The time required for the removal of firing pin 32 from cup 34 is determined by the strength of spring 37 and the rate at which air can flow rearwardly through restrictor means 31.

fter firing pin 32 is removed from cup 34 as shown in FIGURE 2, rotor 27 is free to rotate to the armed position shown in FIGURE 2. This rotation of rotor 27 is accomplished by means of the four rod members 43 and 44. Rod members 43 and 44, being heavier than the remainder of the rotor, tend to spin out and cause rotation of rotor 2'7 in a clockwise direction. Once the rotor has reached the armed position shown in FIGURE 2, rod member 44 falls into slot 46 to lock rotor 27 in the armed position.

To reach the armed position shown in FIGURE 2, the fuze must have experienced a setback force and a centrifugal force developed by rotation of the projectile. The time delay feature incorporated into piston member 28 also acts to increase the time required to arm the fuze.

With the fuze in the armed position shown in FIGURE 2, it will detonate upon impact. When the projectile impacts, housing member 12 and piston member 28 will tend to stop or at least decrease in speed. Body member 23, however, not being directly connected to housing member 12, will tend to continue moving in the direction of flight at the same speed. This movement of body member 23 will compress spring 37 and cause detonator 36 to be driven against firing pin 32. When detonator 36 explodes, lead cup or booster charge 39 is also detonated to in turn detonate the main body of explosive in the projectile.

It is apparent that many modifications can be made to the structure of this fuze without departing from the invention. For example, the spring loaded detents could be removed for those applications in which the added degree of saftey is not required or if the fuze is used in a nonrotating munition. It would also be possible to utilize means other than the unbalanced rotor concept to drive the rotor from the unarmed to the armed position. For example, a spring loaded rotor might be utilized. It is also clear that a carrier member having linear motion rather than rotary motion might be substituted without departing from the invention. Further, the yieldable disk member 38 could be replaced by a coiled spring or by a mechanical latching device. Various other modifications may well occur to those skilled in the art. Although the form of the invention described herein constitutes a preferred embodiment, it will be understood that such changes may be made within the spirit of the invention limited only by the scope of the appended claims.

I claim as my invention:

1. An impact fuze for a rotating projectile, comprising:

(a) a housing member having a first cylindrical chamber formed therein with first and second ends and with the longitudinal axis of said chamber lying along the spin axis of said projectile;

(b) a cylindrical body member mounted in said first chamber adjacent said first end for movement along said longitudinal axis, said body member having a second chamber formed therein;

(c) a cylindrical rotor mounted in said second chamber for rotation from an unarmed to an armed position about an axis perpendicular to said spin axis;

(d) a cylindrical piston member mounted in said first chamber adjacent said second end for movement along said longitudinal axis, said piston member having an annular flexible sealing member mounted around the periphery thereof;

(e) a coiled spring mounted between said body member and said piston member to bias said members apart;

(f) an annular yieldable disc member having the shape of a truncated cone mounted between said body member and said first end to compress said coiled spring and hold said piston member against said second end in a safe position until a setback force acting on said members causes said disc member to collapse;

(g) a detonator mounted in said rotor to lie along said longitudinal axis in said armed position;

(h) a firing pin mounted on said piston member in line with said detonator in said armed position, said rotor having a cup formed therein in line with said firing pin in said unarmed position, said firing pin extending into said cup with said body member and said piston member in said safe position to hold rotor in said unarmed position;

(i) spring loaded detent means mounted in said body member prependicular to said spin axis and extending into slots formed in said rotor to hold said rotor in said unarmed position, said detent means being responsive to the centrifugal force developed by said rotating projectile to spin out and release said rotor;

(j) restrictor means mounted in said piston member to restrict the flow of air between opposite sides thereof, said flexible sealing member allowing air to pass freely around said piston member during movement thereof toward said first end upon setback and preventing air flow in the opposite direction as said piston member is forced toward said second end by said coiled spring after the setback force is reduced whereby the air is forced through said restrictor means to delay the arming of said fuze; said rotor being unbalanced so that the centrifugal force drives said rotor from said unarmed to said armed position when released by said detents and said firing pin; and

(k) means for locking said rotor in said armed position, the impact of said projectile causing said body member to move toward said first end to drive said denotator into said firing pin.

2. An impact fuze for rotating projectile, comprising:

(a) a housing member having a tubular chamber formed therein with first and second ends and with the longitudinal axis of said chamber lying along the spin axis of said projectile;

(b) a body member mounted in said chamber adjacent said first end for movement along said longitudinal axis;

(c) a rotor mounted in said body member for rotation from an unarmed to an armed position about an axis generally perpendicular to said spin axis;

(d) a piston member mounted in said chamber adjacent said second end for movement along said longitudinal axis, said piston member having a flexible sealing member mounted around the periphery thereof;

(e) spring means mounted between said body member and said piston member to bias said members apart;

(f) a yieldable disc member having the shape of a truncated cone mounted between said body member and said first end to compress said spring means and hold said piston member against said second end in a safe position until a setback force acting on said members causes said disc member to collapse;

(g) a detonator mounted in said rotor to lie along said longitudinal axis in said armed position;

(h) a firing pin mounted on said piston member in line with said detonator in said armed position; said rotor having a cup formed therein in line with said firing pin in said unarmed position, said firing pin extending into said cup said body member and said piston member in said safe position to hold said rotor in said unarmed position;

(i) restrictor means mounted in said piston member to restrict the flow of air between opposite sides thereof, said flexible sealing member allowing air to pass freely around said piston member during movement thereof toward said first end upon setback and preventing air flow in the opposite direction as said piston member is forced toward said second end by said axis, comprising:

(a) a housing member having a chamber formed therein with first and second ends;

(b) a body member mounted in said chamber adjacent said first end for movement along said spin axis;

(c) a rotor mounted in said body member for rotation from an unarmed to an armed position about an axis generally perpendicular to said spin axis;

(d) a piston member mounted in said chamber adjacent said second end for movement along said spin axis said piston member having a flexible sealing member for allowing said piston member to move freely through a fluid when moving toward said first end and to retard the motion of said piston member when moving toward said second end;

(e) means mounted between said body member and said piston member to yieldably bias said members apart;

(f) a yieldable member mounted between said body member and said first end to hold said piston member against said second end in a safe position until a setback force acting on said members causes said yieldable member to collapse;

( f a detonator mounted in said rotor;

(h) a firing pin mounted on said piston member in line with said detonator in said armed position; said rotor having a cup formed therein in line with said firing pin in said unarmed position, said firing pin extending into said cup with said body member and said piston member in said safe position to hold said rotor in said unarmed position;

(i) means for delaying for a predetermined length of time the return of said piston member to a position adjacent said second end after said setback force is reduced to thereby delay the removal of said firing pin from said cup, said means for delaying including a restrictor means mounted on said piston member to allow the flow of fluid between opposite sides thereof at a controlled rate; said rotor being unbalanced so that the centrifugal force developed by said rotating projectile drives said rotor from said unarmed to said armed position when released by said firing pin; and

(j) means for holding said rotor in said armed position,

the impact of said projectile driving said body member toward said second end to detonate said fuze.

4. An impact fuze for a rotating projectile having a spin axis, comprising:

(a) a housing member having a chamber formed therein with first and second ends;

(b) a first member mounted in said chamber adjacent said first end for movement along said spin axis; (c) a carrier member mounted in said first member for movement from an unarmed to an armed position;

(d) a second member mounted in said chamber adjacent said second end for movement along said spin axis;

(e) yieldable means mounted between said first member and said first end to hold said second member against said second end in a safe position until a setback force is applied to said members;

(f) a detonator mounted in said carrier member;

(g) a firing pin mounted on said second member in line with said detonator in said armed position; said carrier member having a cup formed therein in line 7 8 with said firing pin in said unarmed position, said (k) means for holding said carrier member in said firing pin extending into said cup with said first memarmed position, the impact of said projectile driving ber and said second member in said safe position to said first member toward said second end to detonate hold said carrier member in said unarmed position; said fuze.

References Cited UNITED STATES PATENTS (h) means for driving said second member to said second end after the setback force dissipates; (i) means for delaying the return of said second member to a position adjacent said second end after said 1,152,917 9/1915 Schneider 102-79 X setback force dissipates, including valve means to 2,709,962 6/1955 Funk et al. 10278 allow free motion of said second member through 10 2,764,092 9/ 1956 Massey 102-73 a fluid when moving toward said first end and to re- 2,790,390 4/1957 Baker 10271 tard the motion of said second member when moving 2,977,883 4/ 1961 Czajkowski 102-79 toward said second end to thereby delay the removal Sald firmg from, Bald P BENJAMIN A. tBORCHELT, Primary Examiner.

(1) means for driving said carrier member from said 1.) unarmed to said armed position after said firing pin G. H. GLANZMAN, Assistant Examiner. is removed from said cup; and 

4. AN IMPACT FUZE FOR A ROTATING PROJECTILE HAVING A SPIN AXIS, COMPRISING: (A) A HOUSING MEMBER HAVING A CHAMBER FORMED THEREIN WITH FIRST AND SECOND ENDS; (B) A FIRST MEMBER MOUNTED IN SAID CHAMBER ADJACENT SAID FIRST END FOR MOVEMENT ALONG SAID SPIN AXIS; (C) A CARRIER MEMBER MOUNTED IN SAID FIRST MEMBER FOR MOVEMENT FROM AN UNARMED TO AN ARMED POSITION; (D) A SECOND MEMBER MOUNTED IN SAID CHAMBER ADJACENT SAID SECOND END FOR MOVEMENT ALONG SAID SPIN AXIS; (E) YIELDABLE MEANS MOUNTED BETWEEN SAID FIRST MEMBER AND SAID FIRST END TO HOLD SAID SECOND MEMBER AGAINST SAID SECOND END IN A SAFE POSITION UNTIL A SETBACK FORCE IS APPLIED TO SAID MEMBERS; (F) A DETONATOR MOUNTED IN SAID CARRIER MEMBER; (G) A FIRING PIN MOUNTED ON SAID SECOND MEMBER IN LINE WITH SAID DETONATOR IN SAID ARMED POSITION; SAID CARRIER MEMBER HAVING A CUP FORMED THEREIN IN LINE WITH SAID FIRING PIN IN SAID UNARMED POSITION, SAID FIRING PIN EXTENDING INTO SAID CUP WITH SAID FIRST MEMBER AND SAID SECOND MEMBER IN SAID SAFE POSITION TO HOLD SAID CARRIER MEMBER IN SAID UNARMED POSITION; (H) MEANS FOR DRIVING SAID SECOND MEMBER TO SAID SECOND END AFTER THE SETBACK FORCE DISSIPATES; (I) MEANS FOR DELAYING THE RETURN OF SAID SECOND MEMBER TO A POSITION ADJACENT SAID SECOND END AFTER SAID SETBACK FORCE DISSIPATES, INCLUDING VALVE MEANS TO ALLOW FREE MOTION OF SAID SECOND MEMBER THROUGH A FLUID WHEN MOVING TOWARD SAID FIRST END AND TO RETARD THE MOTION OF SAID SECOND MEMBER WHEN MOVING TOWARD SAID SECOND END TO THEREBY DELAY THE REMOVAL OF SAID FIRING PIN FROM SAID CUP; (J) MEANS FOR DRIVING SAID CARRIER MEMBER FROM SAID UNARMED TO SAID ARMED POSITION AFTER SAID FIRING PIN IS REMOVED FROM SAID CUP; AND (K) MEANS FOR HOLDING SAID CARRIER MEMBER IN SAID ARMED POSITION, THE IMPACT OF SAID PROJECTILE DRIVING SAID FIRST MEMBER TOWARD SAID SECOND END TO DETONATE SAID FUZE. 